Casting-flask.



Patented Apr. 29, I902.

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UNITED STATES PATENT OF IC CHARLES ALFRED PALMER, OF GRINNELL, IOWA.

CASTINGsFLASK.

- sracrrrca'rron' forming part of Letters Patent No. 699,006, datedApril 29, 1902.

Application filed June 5, 1900. Serial no. 19,115. (No model.)

To aZZ whom it may concern: l

Be it known that I, CHARLES ALFRED PAL- MER, a citizen of theUnited'States of America, and a resident of Grinnell, county ofPowesheik, and State of Iowa, have invented certain new andusefulImprovements in Casting- Flasks, of which the following is aspecification.

My invention relates to improvements in,

casting-flasks, and more particularly to flasks peculiarly adapted forcasting accurate metal dies conforming to dental models, the object ofmy said invention being the provision of simple and convenient apparatuswhereby the mold and resulting casting may be readily made to conform toa model or pattern having a marked undercut or other difficult shape.

I will describe my improvements in connection with a flask especiallydesigned for casting metal dies from underciit dental models. In themanufacture of such dies it is desirable that the sand mold may beeasily formed within the flask and in such manner that the plastermodel, with its undercut portions, may be readily removed withoutinvolving the breakage or disturbance of the mold. This may beaccomplished by forming the mold in sections, so that they can beseparated without breakage, the said sections of the mold beingafterward assembled to make the cast- It will be seen, however, that themold should be formed in as few sections as possible to avoid the chanceof injury thereto. Moreover, the flask should be constructed of as fewparts as possible and in a manner to support the mold-sections intactand admit of their ready separation and assemblage accu rately inposition to complete the mold. The improved .flaskiof my inventionadmirably meets these requirements.

The embodiment herein shown may be briefly described as consisting ofbut three separable parts,,- preterably made of metal, whichrespectively receive the-plaster cast or dental model and the twosections ofthe sand mold conforming thereto, the last named parts of theflask also conforming as'to their line of separation'to the outline ofthe dental model. These flask-sections have accuratelyfitting innerretaining-walls, which support and retain the mold-sections andfacilitate wherein-- Figure l is a view in perspective, showing theflask-sections inverted and about to be assembled to form the mold. Fig.2 also is aperspective view showing the completed sand mold within theflask, the sections thereof being separated to permit the removal of themodel; and Fig. 3 is a sectional view through the flask and sand moldwhen ready for casting.

Similar parts are therein designated by the.

same letters of reference.

The complete flask consists of three sections or parts, preferablyconstructed of iron, steel,

or brass, comprising the ring A and the conforming front or section B,together forming a sectional drag, and the cope or cone 0, the twofirst-named sections fitting upon and being separable from the lattersubstantially along a given or horizontal plane' These parts are adaptedto be removably secured together b'y-pins E F, fitting in lugs or earsprovided upon the said sections. Sections A'B'are constructed with wallsof moderate thickness, the abutting faces of the inn'erwalls atB beingsemicircular] y shaped to conform generally to the outlinejof the dentalmodel or plaster cast D, surmounting the conical plaster base D.

These walls are centrallycut away in ahori:

zontal planeppermitting the formation of a practically continuous sandmold when the sections are assembled, which mold naturally separatesalong the line of the abutting walls. Section C is provided with aninterior tapering opening, conforming generally in shape to the frustnmof a cone, with a flattened rear portion, in which opening the plastercast accurately fits. It will be understood that no top or bottom isprovided for the flask-sections.

With the aid of the'drawings and the foregoing description the use of myimproved flask will now be made clear. Having inserted the plaster castD of the mouth in cone 0,

which cast is prepared in a well-known manner not necessary to beexplained herein, the several sections are assembled and secured inplace by means of pins E F, the flask being placed in an invertedposition-that is, resting on the smaller end of the cone. Finemolding-sand is then placed first in ring A and carefully tamped downsufliciently to form a finished section of the mold, a quantity of sandalso being placed in section B temporarily to support the mold-sectionthus formed in ring A while the sand is being tamped down. Pins F arethen withdrawn, permitting the removal of the front or section B,together with its contained portion of the sand mold which parts orseparates along the line of the engaging faces of sections A B. Theexposed or curved outer edges of the sand-mold section in ring A arethen shaped by the fingers or suitable tools to present a sharp evenparting-line, and the exposed edges are dusted over with French chalk b,or tissue-paper is placed over said edges to prevent the other sectionof the sand mold from adhering thereto. Theincomplete portion of thesand mold in section B is removed,and said section is replaced in itsformer position. Molding-sand is then filled into said section andcarefully tam ped down about the exterior edges of the sand mold andundercut portions of the model, thereby completing the mold. Theflask-sections may now be separated after removing the pins, and bytapping the walls of sections A Bit will be found that the sand moldwill separate along the parting-line conforming to the outline of thedental model and the engaging interior walls of said flask-sections,which serve to support the sections of the said mold. The plaster castis now readily removed from the mold and its containingcone G withoutdisturbance of the lip or protruding portion conforming to the undercut.YVith a little care and experience, however, a simpler method of usingthe flask than that just described may ordinarily be practiced. Thisconsists in forming the complete moldsections in A and B at oneoperation. Then after sufficiently tamping down the sand, inverting theflask, and removing the pins the mold and flask sections A B may beslightly separated to withdraw the dental model D from the mold. Themold-sections are rarely disturbed by this operation, if carefullyperformed, and may be immediately reassembled for casting, the seam orparting-line being previously smoothed over should it be required.

It will be seen that the mold is formed in but two sections, thusafiording but little chance for injury thereto in separating andassembling the same, as well as readily securing an accurate sand moldfrom a model having a decided undercut or other diffieult conformation.

By shaping the engaging interior portions of the flask-sections tocorrespond or conform to the outline of other models it will beperceived that three-section molds may readily be formed therein, as inmy improved dental casting-flask, which, moreover, may be utilized, ifdesired, by forming a portion of the sand mold in the third section orcone 0, as required in many classes of work. I have used the terms cone,ring, 810., herein merely to designate flask-sections, which will be theequivalents of the specific forms set forth.

The flask-sections are reassembled and accurately secured together bymeans of the pins, after which the metal die, ofzinc or alloy, is castby pouring the melted metal through the opening in the smaller end ofcone 0.

Having now described one embodiment of my invention, I claim as new, anddesire to secure by Letters Patent, the following, together with allsuch modifications as may be made by more skill or are by law implied:

1. A casting-flask of the class described, comprising three separatesections, to wit, a cope having a substantially flat parting face and adrag fitting said cope, comprising two separable sections having curvedabutting inner walls shaped to conform to the curved outline of themodel, substantially as described.

2. A. casting-flask of the class described, comprising three separatesections, to wit, a cope having a substantially fiat parting face and adrag fitting said cope, comprising two separable sections having curvedabutting inner walls depressed or cut away below the plane of theparting face and shaped to conform to the curved outline of the model,substantially as described.

3. A casting-flask for undercut models or patterns, consisting of threesections, to wit, a cope 0 having a substantially fiat parting face anda drag fitting said cope comprising two sections A B, the outer andinner walls of the section 13 having the general form of concentric arcsof circles and the section A having anouterwall conforming substantiallyto the adjacent portion of the cope, said section A removably fittingupon section B, whereby a parting is secured conforming to said curvedinner walls, substantially as described.

4. A dental casting-flask comprising three separable flask-sections, ofwhich the cone C is separable from the other sections along a horizontalplane, and sections A and B for receiving the sectional sand mold, areseparable from each other substantially at right angles with said plane,along a curved line conform ing to the exterior outline of the dentalmodel, said sections A and B being provided with a supporting-wall forthe sectional sand mold, conforming likewise to the exterior outline ofthe dental model, substantially as described.

5. In a casting-flask, the combination with flask-section C, of sectionsA B wherein a sectional sand mold may be formed, said sections fittingupon section 0 substantially in a horizontal plane, the sectionsA Bbeing separable and fitting accurately together substantially along thecurved outline of the model from which the casting is to be made, whichoutline is marked by a curved supporting-wall, and means for removablysecuring the flasksections in their relative positions, substantially asdescribed.

6. In a flask for casting dies from undercut dental models, thecombination with a cone 0 adapted to receive the cast bearing the dentalmodel, of a ring or section A and a front B wherein the sectional sandmold is formed, the said latter sectionsbeing interiorly shaped to fittogether along a curved line conforming substantially to the exterioroutline of the dental model, and means for'removably securing theflask-sections together, substantially as described.

7. A dental casting-flask consisting of three sections, to wit, a cope Osubstantially in the form of a cone having a flat parting face, and adrag having a flat parting face and consisting of two sections A, B, theouter and inner walls of the section B having the general form ofconcentric arcs of circles and the section the metal die may be cast, ofa ring A, the for- Ward portion of which is shaped to conformsubstantially to the exterior outline of the dental model D, a front Bfitting thereon, whereby a parting-line is insured which admits of theuse of a two-section sand mold in parts A and B, and means for removablysecuring the flask-sections together, substantially as described.

Signed by me at Grinnell, Iowa, this 6th day of February, A. D. 1900, inthe presence of two subscribing witnesses.

CHARLES ALFRED PALMER.

Witnesses:

S. A. PALMER, R. M. HAINES, Jr.

